Shoe filler composition and method of making and applying the same



June 19, 1962 E. D. SACKETT 3,039,885

SHOE FILLER COMPOSITION AND METHOD OF MAKING AND APPLYING THE SAME Filed March 51, 1958 $1181; 2. Jam 6% 3? M fliZV 3,039,885 SHOE FILLER COMPOSITION AND NIETHOD OF MAKING AND APPLYING THE SAME Ernest D. Sackett, Winchester, Mass, assignor to North American Chemical Company, Cambridge, Mass., a

corporation of Massachusetts Filed Mar. 31, 1958, Ser. No. 725,050 5 Claims. (Cl. 10638) The art of making and applying shoe filler compositions dates from the beginning of making welt shoes, and has continued until the present day as an integral and essential part of the making of all of the various types of welt shoes.

The necessity for such a filler lies in the characteristic formation, in the welt type of shoes, of a cavity within the area defined by the Welt and between the inner and outer soles of the shoe. This cavity must somehow be filled, in order for the shoe to sustain the weight of the wearer.

Many fillers have been proposed and used, with widely varying degrees of success, and failure.

In the early days of welt shoe manufacture, it was proposed and practiced to prepare a mixture of a granular body material and an adhesive binder, which could be applied to fill and conform to the shoe cavity. And such, in general terms, is the character of present-day shoe filler compositions. But, in order to make such compositions amenable to application, adhesion and conformation to the shoe cavity, various devices and conditions have been found necessary to resort to, and these are attended by numerous detrimental conditions, either in operation or in the result obtained.

In general, a binder has been used for the granular material which would be fluid and adhesive under the conditions of preparation and application to the shoe and which would subsequently become and remain solid in the shoe bottom, under other conditions such as the conditions of wear and use of the shoe.

Before such filler compositions of the prior art can be used and applied to the bottom cavities of shoes, they must be heated to melt the binder component and thus render it fluid. Such heating must of course be to temperatures below those at which the shoe structure, the granular body material and the binder itself would tend to deteriorate. To do this, it has been found necessary to employ hot water or steam, which is added directly to the filler composition to impart the required amount of heat, without excess temperature. Such steam or hot water, while effective to heat the filler compositiomat the same time mingles intimately with it. Consequently it becomes a dominant component of the filler composition itself. This is beneficial during preparation and also during the application of the fiher composition to the shoe cavity, with some qualifications. But, once in the shoeespecially while hot, but even after cooling to room temperaturesthe water or steam may separate and penetrate the shoe structure. In any event, it evaporates and continues to evaporate, which presents difiiculty. There are also other rather obvious disadvantages connected with the necessity of using either hot water or steam.

The binders used in these compositions, in addition to binding the cork, also required lubrication, for mobility of the cork particles when the hot mass was subjected to the distributing pressure, upon filling the composition into the shoe. Such lubrication involved a permanently liquid component of the filler, such as oils and waxes. Several patents have been issued on means of increasing only temporarily the lubricating properties and volume of the binde These have involved various water-sensitive ma terials, which would swell, or volatile solvents of the binder, and the like. But all of these require the presence nite States Patent ice of steam, condensate, or hot water to activate them. Al though extensively used, there have been many problems connected with their use.

In the shoe factory, solid cakes of the filler, in a mass, are loaded into heating devices (conditioners) and subjected to heat and moisture; the heat to melt or soften the mixture, and the moisture to activate the water-sensitive components. The actual amount of moisture used is usually in excess and is added from time to time as determined roughly by the operator. There is no possible means or measure by which he can control it. Consequently, there has been little accuracy possible either in the temperature of conditioning or the amount of moisture added to the filler. For this reason the filler is not always in prime condition for application to the shoe. An excess of water often occurs which, under pressure of the spreading tool or shoe press plate, seeps through the tack holes in the innersole, the stitch holes in the welts, etc. Moreover, the water is often added at a temperature which is out of line with the mixture and insuflicient time is allowed for its proper correction and reaction with the binder, resulting in rough bottoms.

A further source of difiiculty, which is common to all of the hot filler compositions of the prior art-though especially when hot water or steam is used or present during preparation or application to the bottom cavity of the shoe to be filled therewith-is that such compositions are subject to selective segregation and fluid flow of one or more of the liquid ingredients of these compositions. This need take place only to a very slight extent, and in a single instance, to result in seepage or penetration to other parts of the shoe, as above mentioned, and it might cause staining and rejection of the finished shoe.

In addition to these limitations and difiiculties of the prior art, recent changes in the methods and materials of shoe construction have made imperative the invention of a shoe filler which shall require no moisture and no volatile solvent for activation.

One such change is the substitution of paper based materials for leather as an innersole material. These paper based products (and leather blanks, as well) are not channeled to form the raised lip or welt. A pre-forrned rib is cemented to the otherwise flat surface instead (Patent No. 1,998,125, April 16, 1935, to Frank F. Eno). The adhesive used for this purpose is easily attacked or upset by volatile solvents and to a certain extent the base material itself. Hot water in excess has an adverse effect on the stability of the base material, especially if under tension. Accordingly, this type of welt shoe construction is particularly susceptible to attack and deterioration by water, steam or volatile solvents in the shoe filler composition applied to them in the shoe bottom cavity.

A further change in the industry is the decrease in thickness of the innersole material which the pro-formed rib has made possible, for it follows that the thinner the innersole the more and greater are the pressures of walking which are transmitted to the bottom filler. Furthermore, these thinner materials are easily chipped by the mechanical tack puller, which removes the lasting tacks just previous to the bottom filling operation. In the case of paper based innersole material this chip can be substantial in size, making a perfect path for water or any fluid component of the binder, which might be free, to permeate through and to the interior of the shoe, especially F when the bottom filler is hot and subjected to pressure.

Another recent change is the introduction of synthetic fibers in the thread used to sew the welt to the innersole. Such threads do not effectively seal the awl hole, and this leaves a path for water (or any other free liquid) to pass through and beyond the innersole and stain the shoe upper.

aosasee These are well known difliculties with shoe filler compositions, but they have not heretofore been overcome by the prior art.

In view of these considerations, it would be desirable if shoe bottom filler compositions could be given a consistency, during the stage of their preparation, at which they could be readily and uniformly compounded and mixed and shaped; and if, in the subsequent stage of conditioning them and applying them to the shoe bottom, such consistency of the initial preparation stage could be restored, without hot Water, steam, condensate or any volatile solvent, and without overheating or high pressures, to such degree as to permit: the ready manipulation of the composition, in the desired quantity to fill the shoe cavity; the quick application, spreading and conformation of the charge, by hand or by mechanical pressure methods, to all of the shoe cavity surfaces; also the formation of a smooth top surface, capable of likewise Wetting, conforming and adhering to the surface of the outersole, when the latter is applied thereto and lasted into the shoe; and the capacity of finally setting to the condition of a resilient, uniform, solid mass, integral with the rest of the shoe structure, free from any alterations, such as segregation, seepage, evaporation, shrinkage, craking or hardening, but remaining flexible, compressible and form-retaining under all normal atmospheric conditions and under the weight and stresses of wear in the shoe.

.It is an object of this invention, therefore, to overcome these difi'iculties or deleterious conditions of using the shoe filler compositions of the prior art and also to render them more definite in composition and uniform in their properties, generally, both as conditioned and as applied to the shoe cavity and thereafter in the finished shoe, the bottom cavity of which has been filled therewith.

It is a principal object and purpose of this invention to avoid the incorporation or use of water, steam or condensate, or other volatile liquid or solvent, in the shoe filler composition, either in the operation of preparation or conditioning it subsequently for use and application to the bottom cavity of the shoe, at any time or for any purpose.

A further object of this invention is to provide a binder component for the granular body material Which shall be continuous, tough and flexible under all of the conditions of use, application and wear of the finished shoe containing it, without presenting any free or segregatable liquid or becoming brittle, at any time, under any and all of the conditions normally and usualy involved.

More specifically, it is an object of this invention to impart the charcteristic properties of plasticity and of plastic flow-as distinguished from free fluid or liquid flowto the binder component of shoe filler compositions.

Another object of the invention is that the binder component shall not be subject to any separation or segregation of any of its ingredients but shall form a mutually soluble or compatible medium, of uniform composition and consistency, which shall be plastic at elevated temperatures and gradually become firm and solidify (upon cooling through and below such temperatures) so as to constitute a homogeneous solution, followed by a gelatinous precipitate and/or gel structure, which is permanent.

W Another object is to facilitate the combined operations of conditioning and then applying the filler composition to the bottom cavities of shoes, whether by hand or, more especially, under pressure or. mechanically, as in the various types of shoe filler presses which are now used, to this end. 7

"Further objects of the invention will appear from the following disclosure.

It is now found, by this invention, that the above objects of invention may be attained by suitable appropriate selections, controls and conditions, of certain raw materials, severally, which are to be used in compounding the new shoe filler composition: and through certain new procedures and conditions of treatment in preparing the composition initially and also in subsequently conditioning it and applying it to the shoe bottom cavity.

In the accomplishment of these objectives, purposes, conditions and results, it is found as a part of this invention that each of the raw materials in the binder component must be not only insoluble in water, but shall not be sensitive to water in any way. In fact they must be water-resistant and even water-repellent. They must also be free from any component which would be volatile under any of the conditions of operation involved.

It is also found that the binder component should manifest a self-sustaining surface tension and consistency, per se, at all times and under all conditions, and that such a binder component can be prepared. To this end, the solvent medium of the binder component must not only be devoid of free liquids, under all of the conditions of preparation, treatment and use, but must also be restrained from free liquid flow or penetration of adjacent areas of the shoe. :Such restraint is effected in the present invention by dissolving normally solid materials therein, namely resinous materials, as hereinafter described. Such resistance to free fluid flow would be indicated in the resulting solution of the resinous material in the solvent material, (as shown on the acompanying graph of the drawings, :FIG. 1) for example by a viscosity of, let us say, not appreciably less than centipoises at temperatures approaching 300 F., and higher viscosity values at lower temperatures; and by a surface tension which is manifestly suflicient to resist free liquid flow, even at elevated temperatures of 200 to 300 In addition, the solvent medium, which is inherently of high boiling point as a charcteristic of its non-volatile properties, is also capable of dissolving the other, solid ingredients of the binder component, at temperatures approximating or above their melting points, to form a homogeneous solution or a compatible mixture therewith which is characterized by being free from any tendency to segregation or separation then or thereafter.

It is found that by employing in the binder component certain normally solid materials (usually resinous in character), which are both water repellent per se and et soluble in the solvent medium an appropriately mobile solution is attained. The characteristics of this mobile medium may be controlled so as to possess and exhibit further restraint upon its flow properties, as above described, relative to those of the solvent medium, per se, and these may be regulated, in terms of the proportions used and with reference to temperature and pressure gradients imposed during preparation and subsequently in conditioning and applying to the shoe bottoms.

It is now further found that, by incorporating certain tough, film-forming materials, which characteristically manifest -a melting point, per se, above that of the other ingredients of the binder component, above discussed, and which are not water-sensitive but which are capable of being dissolved or intimately dispersed in the solvent medium (or mobile medium, containing resinous additions, as above described) to form a homogeneous solution or compatible mixture, at elevated temperatures, a binder component or matrix for the solid granular body material may be prepared which will exhibit the above described desirable qualifications and serve the PLHPOSBS and objects of the present invention, as hereinabove and hereinafter set forth.

Such a homogeneous solution of the solvent medium, resinous material and film-forming material at elevated temperatures (above, for example, the melting-point of the film-former) manifests the characteristics of plasticity and plastic flow and high surface tension, all of which are eifective to inhibit any uncontrolled spread over surfaces or permeation into or through porous surfaces or even small apertures or crevices such as the tack holes and awl holes in the innersoles or uppers of the shoes, as above mentioned.

Moreover, upon cooling such plastic solutions or mixtures or mobile media to lower temperatures, below the melting point, per se, of the film-former, for example and again, below the melting point of the resinous material), they characteristically pass through a stage of gelatinous precipitation of the solid components which they contain in solution. The film-former tends thus to separate, throughout the mass and then form an incipient structure. Upon further cooling it forms a solidify ng gel (which is generally recognized as having a SOlld, honeycomb structure) made up of the thus separately solidifying film-former, to constitute a solid, continuous, uniform film structure throughout the whole. The sol vent medium and resinous material from which it forms will fill and form the matrix of this gel structure subsequently, on further cooling, solidify to a firm SOlld, as a unitary embodiment of the binder component.

This continuous, tough, film-forming agent, in being homogeneously soluble in or compatibly miscible with the solvent mobile medium of the binder component and, from such condition, going into the form of a gelatinous precipitate, and thence into a solidifying ge structure imparts a film structure to such gelatinous precipitate and to the gel structure solidifying therefrom, so that it has a continuous, tough, solid structure throughout the whole and hence it manifests these properties in three dimensions.

In the art of oils, fats and waxes, it is common to refer to certain of them as manifesting the property or stringiness or the property of lunginess.

The former expression generally denotes that a material, more or less fluid in character, when subjected to tension in one dimension, will elongate in that direction, accordingly, without rupture, on the one hand, but with increasing resistance to such tension, in proportion to the degree and rate of elongation, and also without tendency to return to its former shape or dimensions upon release or relaxation of such tension, that is, Without manifesting elasticity.

This term is, therefore, descriptive of a high degree of resistance to change, shape or disposition, that is, to flow, or viscosity.

The latter expression, lunginess, generally denotes a material which by itself, tends to draw together into an integral, rounded, smooth-surfaced, mass, and which, accordingly, presents resistance to deformation, flow, enetration, or even severance of one part of the mass from another. This term, therefore, describes a condition of high surface tension, cohesion, and either high resistance to flow or even incapability of flow, without rupture.

By plastic, plasticity or plastic flow, in the present specification is meant, consonant with the usually accepted meaning of these terms, that the material in question, (whether the binder component, or the complete filler composition, containing the granular body material) has and manifests the ability to flow but only to fiow as a unit, and only when subjected to a moderate degree of positive differential pressure, or yield value, without separation or aggregation of any of its ingredients, and such flow ceases Wherever and whenever and however the actual dit'ferential pressure thereon may fall below such yield value.

In brief, such compositions are form-retaining, but under conditions of differential pressure which are appreciable, they will commence to yield to such pressure and flow, but as soon as they move away from the area or influence of such degree of pressure, they will cease to flow. For example, a large mass of the material, otherwise free, but pressed downwardly by a positive pressure of some ounces (when hot) or pounds (when cold) from above, will yield and flow laterally in all di rections uniformly. But when it has moved outwardly or away from the impending source of pressure, it will cease to flow, in such outward areas. Likewise, when the filler composition is filled into the shoe bottom cavity, under hand or machine pressure, it will spread outwardly quickly and evenly, under the pressure of the spreading tool. But when and where it goes beyond such pressure influence, it will abruptly stop and not fiow farther. Similarly, in being spread on an open area, it will spread quickly and evenly but it will abruptly cease to flow if the areas or open spaces become limited in cross section.

As applied to the shoe filler compositions of this invention, one may say that the plasticity or capacity to deform, under pressure, is such that, at temperatures of the boiling point of water and above, the material is subject to plastic flOW, upon the application of a differential pressure or shear of about a pound per square inch, as representing that which an operator would ordinarily apply in spreading and pressing it into the shoe bottom cavity. At temperatures below the boiling point of water, the compositions are subject to deformation under pressures, but only to pressures of a higher order, such as the weight of the wearer of a shoe in which the composition is incorporated, say a hundred pounds per square inch, more or less, and then not to the deformation of plastic flow but to the deformation of shape without rupture.

For example, at ordinary room temperature a cube of the finished bottom filler composition, upon eing subjected to about 30 pounds pressure or some 57 poupnds per squareinch flowed out in all directions; but, at a distance of about A", (where the differential pressure gradient had fallen below the yield value) such fiow ceased and presented sufiicient back pressure upon the actuating source to prevent further flow therefrom.

In accordance with the present invention the binder component is characterized by having a high boiling point, and by being free of any low boiling solvents or the necessity of adding any volatile matter whatsoever, such as steam or water. It is therefore completely resistant to volatilization at any of the temperatures em ployed. It is also water resistant or water repellent and hence free of materials which might be water sensitive. It is also characterized by free flow, per se, at the high temperatures of preparation of application of the compo sition, but manifests unitary flow at all times, restrained by a high viscosity and surface tension, or by actual plasticity and plastic flow at all temperatures. It is, moreover, not subject to separation or selective flow of any of its constituents, at any stage during or after compounding and mixing the same.

Typical substances which are suitable as thermoplastic solvents in the binder component for the present shoe filler composition, as above described, are found in the hydrocarbon residues obtained in the refining of petroleum oils, to prepare lubricating oils therefrom. These solvents are inherently aromatic or naphthenic in chemiical composition, and characteristically free from all volatile matter, such as volatile liquid solvents, etc. and of course from any and all possible association with Water. They are Water resistant and in fact Water repellent, and have boiling points considerably above the range at which shoe filler compositions can be practically compounded or applied to the shoe. They also exhibit a high degree of viscosity and surface tension at such temperatures, and plasticity and plastic flow, per se, at lower temperatures.

These solvents are inherently aromatic or napthenic in chemical composition. They are usually separated from the parafiinic constitutents of petroleum lubricating oil stock by any one of several well-known selective solvent processes. Since they represent the undesirable constituent of quality lubricating oil they are referred to as residues.

NuSo 250 is represented to be a phenol extract of lubricating oil. A description of the process may be 2' found in the The Science of Petroleum-Oxford University Press, New York, 1938. The various Dutrex fractions are represented to result from the products of one or more selective solvent processes. Similarly the Ciro oils are products of selective solvent extraction. Materials of this type exhibit quite a range of viscosities. Their sp. gravities will generally run from .03 to 1.1 and possess aniline points in the range of 70-200 F. and in mixed aniline points of 80 Eda-95F. Having lower aniline points and being of lower molecular weight than the paraffinic fractions, they exhibit solvency for the type of materials described as film formers in this application, as well as being superior solvents for the types of solid resins used. The aniline points given above represent practical commercial ranges. But for purposes of this invention solvents of even lower aniline points, and consequently of greater aromatic characteristics, could be advantageously used.

These substances serve to dissolve the film-forming component of the composition, at temperatures about or above its melting point, to form therewith a true solution or compatible mixture, so as effectively to develop the characteristics of plasticity and plastic flow, of the whole.

As instances of such substances, may be cited NuSo, Dutrex 20, 21 and 22, and Circo heat transfer oils.

All of these substances will exhibit an initial boiling point, at standard pressures, above 400 F.-or, for example, not less than about 120 C. (200 F.) at only 1 millimeter of pressure, demonstrating that they are free from any volatile matter which could possibly be liberated under the conditions employed in carrying out the present invention.

The viscosity of these hydrocarbon solvents for the filmforming material may be increased by dissolving higher melting point solids therein, such as resins. Various resins, including those heretofore used in shoe filler compositions, more especially for their adhesive qualities, such as common rosins, polymerized rosins, hydrogenated rosins, various by-product residues derived from the preparation of resinous products, synthetic resins, such as the phenol and alkyl resins, and the like, may be included and employed as supplementary to the binder component as above, to increase the viscosity and to regulate and control the plasticity or plastic flow of the same, and of the tiller composition, as a unitary Whole, with due consideration to costs and consequent economies, proportions, and the stabilities and consistencies allected thereby.

The film-forming component of the present shoe filler composition is characterized by being normally solid and having a melting or softening temperature, per se, which is at, about or above all of the temperatures involved in the preparation and use of the composition. t is not water-sensitive, but resistant to Water or steam, although it is not subjected to either, in view of the anhydrous character of the present composition and all of the operations which are carried out therewith. It is soluble in the hydrocarbon solvents of the binder, above described, at high temperatures, but its concentration rapidly exceeds such solubility, upon cooling and before the other constituents of the binder medium solidify, so that it tends to separate, from solution, first as a gelatinous precipitate, which rapidly takes on the characteristics of a stiff gel formation and forms the honeycomb structure, typical of gels.

Such film-forming materials which are suitable for use in the present invention include vinyl-chloride-vinyl-acetate, ethyl cellulose and various polymers of styrene and its homologues. All are normally hard, solid bodies, per se, at ordinary temperatures, but upon dissolving in the solvent or the binder and separating therefrom in thin films, they form gelatinous precipitates and gels, which acquire a high degree of flexibility and toughness. This is due in part to such physical filmy, continuous formations and in part to the plasticizing etfects of the hydrocarbon solvents and resins, from which they thus separate, but which still constitute a matrix in which the honeycomb, cell and film structure forms and is permanently encysted.

In the practical carrying out of the invention, in con mercial operations, it is convenient to heat the solvent and other ingredients of the binder component to the melting point or sufficiently above, to render the whole uniform. This will provide a large part if not all of the heat required for the subsequent steps of operation. This will include not only the solvent material and the resinous materials for modifying and controlling the viscosity and plasticity, but also the film-forming material, which still further enhances the plasticity of the ixture and ssures plastic ilow therein, in contrast to fluid flow, upon its addition.

The resulting solution or compatible solvent mixture is agitated or stirred, if necessary, to render it of uniform composition and consistency.

The mixture is heated, preferably before addition of the film-forming material (which tends to give stringiness and lunginess, as above defined, to the mixture at this stage) to a temperature sufficient to dissolve the film-forming material, as it is added, and/ or to bring the film-forming material to approximately its melting point, or slightly above, as the case may be, (though Without being sufficient, in degree or time, to degrade it so as to reduce its melting point or film-forming characteristics above described) in which case it becomes a matter of mixing wo liquids which are mutually soluble and which are mutually compatible in a wide range of proportions, especially while at temperatures above their melting points.

The film-forming material, being normally solid and at room temperature, upon addition to the hot, solvent binder medium, will have the effect of lowering its temperature, while at the same time dissolving therein, or melting itself, and dissolving, if at temperatures above its melting point. This preliminary heating, followed by cooling of the solvent mixture and solution effectively safeguards or prevents tendency for the film-forming material to be overheated, or degraded, in chemical composition or physical structure, which is apt to occur when at or above its melting point, per se.

The binder component, as thus compounded and conditioned, is further mixed to uniformity and added to the granular body material, such as ground cork, or vice versa. This admixture of ground cork Will still further cool and thus increase the plasticity of the binder component, as well as additively stiffen the consistency and behavior of the composition as a whole. For example, the viscous to plastic, continuous mass of binder will be subdivided by the cork into thin, tough continuous films covering and between the cork granules, as they become dispersed throughout the whole mass of the mixture, and thus be extended and separated from each other, While serving in turn, to separate the dispersed granules of cork. But the residual heat is usually sufficient to maintain the plasticity and plastic flow of the binder component and also of the complete filler composition, for the purpose of mixing and also the development of a uniform plastic product-if properly retainedthough it may be supplemented by additional external heating, as by using a heat-jacketed container.

While still hot, the charge as thus prepared may be subjected to pressure or a differential stress, as a mass, and thereby caused to undergo plastic flow. In this condition, for example, it may be extruded in the form of a continuous column, or sheet, of round, rectangular, square or other cross-section and of such size as desired. This extruded column may then be cut oh, in loaves, sheets, or other shapes of predetermined size and weight. After cooling, these may be packaged, stored or shipped, and will be ready for subsequently conditioning, by reheating, and filling into the bottom cavities of shoes. Various compositions may be made in accordance with the invention, as follows:

99-75 solvent and plasticizer, by weight 1-25 film-forming material, by weight 50% i, by volume, of granular body material such as ground cork in the finished product For example:

48 parts, by weight, NuSo 250 30 parts, by weight, Polypale (polymerized) rosin 20 parts, by weight, Melhi resin (polymerized) rosin residue 1.6 parts, by weight, ethyl cellulose 125 parts, by weight, Dutrex 21 40 parts, by weight, Polypale (polymerized) rosin parts, by weight, vinyl chlorid (96%)-vinyl acetate (4%) resin 55 parts, by weight, Dun-ex a 40 parts, by weight, Melhi resin-polymerized rosin residue 26 parts, by weight, Piccolastic E-l The ranges of the binder component given in Examples 1-3 above vary between the following percentage limits by weight:

l.6%l7% film forming material 98.4%83 solvent and plasticizer The percentage range of solvent and plasticizer given in the examples is composed of 24% to 51% by Weight of solvent resin and 49% to 76% by weight of solvent plasticizer.

NuSo 258, as stated above is the residue of highest viscosity obtained from the phenol process of extracting petroleum oils, in making lubricating motor oils.

Polypale (polymerized) rosin is the product obtained from the process for polymerizing the unsaturated resin acids found in natural rosin.

The process causes a portion of the unsaturated resin acids to react with each other through their double bonds to form polymers. The exact nature of these polymers has not been worked out. But the concentration of such polymers in the Polypale (polymerized) rosin, above indicated, is approximately 40%, the remainder being the normal constituents of rosin.

The Melhi resin is the lower layer, obtained in the formation of Polypale (polymerized) rosin, as just described, and separates as a residue therefrom.

Dutrex 21 is a petroleum hydrocarbon plasticizer, as above described.

Piccolastic 13-125 is the name for one of a series of resins produced from styrene type materials which contain homologues of styrene and substituted styrenes, such as those obtained from the fractionation of so-called crude solvents from light oils scrubbed out of coke oven or gas house gases.

With these compositions, as specific examples, the solvent and solid plasticizers or resins, etc., which are soluble in or miscible therewith, are first heated sufficiently to efiect solution and miscibility, and agitated to develop a uniform consistency. The solution may then be heated to about 325 F. in a directly heated kettle. The charge is then pumped to a jacketed vessel, having an agitator, and the temperature adjusted to about 300 F. The ethyl cellulose may be added at this stage which will lower the temperature somewhat, but this will be maintained at or about 275 F., with agitation, until complete solution and miscibility of the ethyl cellulose and the rest of the charge is assured. If added at temperatures lower than its melting point, the ethyl cellulose simply dissolves in the other fluid binder components. This may require a longer time but avoids any possibility of degrading the ethyl cellulose, by overheating. In either case, the whole charge becomes uniform and of increasing consistency and plasticity, which develops further, as the temperature is lowered.

Preferably the charge will not be held at high temperatures or longer than necessary. Accordingly, when thus compounded, heated and mixed, the binder oomponent may be poured into the required amount of ground cork, usually of about an equal amount, by volume, sufficient to fill the voids between the cork granules and separate and disperse them, as above pointed out. The proportion of binder component to cork is not suflicient to make the binder component dominant or independent of the cork but is sutficient to overcome the resistance of the cork granules to flow over and past one another as in direct, dry Contact. Or, the fiuid binder component may be put into a heated mixer and the cork granules added to it with suitable agitation of the whole. In either case the charge is thoroughly mixed.

The charge, as thus obtained, may be withdrawn from the mixer, and shaped or molded, as desired, as above mentioned. The loaves or sheets may be cooled and hardened by water sprays, if desired, without doing them any harm for they are Water repellent and it will flow oil, and be evaporated therefrom by the residual heat.

For subsequent application to shoe bottoms, the loaves of filler, as thus provided, are simply heated, as by contact, electrical resistors, radiant heat or any other suitable source or" dry heat, to the desired temperature for the development of plasticity and plastic flow, of the preferred consistency. The required amount is separated from the mass with a knife or spatula and laid into the shoe cavity. It is then spread around the cavity and pressed in and smoothed ofi, either by hand of mechanically by means of the usual shoe filler press, which subjects the charge to a short sharp compression or blow, in a fraction of a second. Thereupon the charge undergoes a spontaneous, unitary plastic flow, as a whole, almost instantaneously into and over all of the surfaces of the shoe cavity, conforming and wetting the same intimately and completely and filling it to the top, level with the upper margin of the welt, and then stopping such flow abruptly, as the pressure is stopped, or whenever and wherever the pressure falls below the requisite threshold or yield value for plastic flow of the filler composition at the temperature at which the operation is carried out.

By the present invention, therefore, a new type of shoe filler composition is prepared, in which no water, or aqueous component or agency such as steam, is present or needs to be employed at any stage of its compounding, conditioning or application to the bottom cavity of the shoe. it is likewise free from other volatile components or volatile solvents of any kind. It is prepared by compounding a binder component which is characteristically solid but which becomes thermoplastic at elevated temperatures, thus manifesting plastic flow, as differentiated from fluid or liquid flow. The binder component typically comprises a solid, thermoplastic filmforming component, compatibly dispersed or dissolved in a normally solid, thermoplastic solvent ehereof, to develop a plastic consistency. The binder component thus acquires a consistency, subject to thermoplastic flow, at elevated temperatures, and on cooling the dissolved filmforming component passes over into a solid gel formation, which is form-retaining below such temperatures. The composition is completed by dispersing granular body material, usually ground cork, which is formretaining, elastic, porous, tough and light in weight, into and uniformly throughout the plastic binder component, while heated, in such amounts as to be coated, covered,

assesses protected and occluded by the plastic binder component, as a thermoplastic matrix for the whole, thus constituting the ultimate shoe filler composition, in a plastic condition, ready for molding into shaped masses, such as loaves, and ready, upon subsequent conditioning by dry heat, for direct application to fill the bottom cavities of all types of welt shoe constructions.

The accompanying drawing is presented for the purpose of showing graphically the several and cumulative effects of temperature and of adding and proportioning the several elements which go to make up the binder component of the shoe filler composition of the present invention.

Curve 1 plots the several and successive viscosities, at increasing temperatures from left to right (as determined by means of a Brookfield viscosimeter) of the binder componenn'without the addition of the film-forming elementor component, of Example 1.

Curve 2 plots the several and successive viscosities, at increasing temperatures from left to right, obtained with the same binder component, including the film-forming element or component of Example 1, namely 1.6% of ethyl cellulose, which was of the 100 second grade, per se, as technically classified,

From these curves it will be readily apparent that, as the binder component (without the film-forming component) is heated up, the viscosity drops. But, even at 300 F., and above, it is still appreciable.

The addition of the film-forming component (curve 2) increases the viscosity readings, under all conditions, very decidedly. Upon cooling the binder component containing it, from 300 F., or above, for example, the viscosity is not only higher to start with but rises more rapidly and to a much greater degree, down to about 200 F. At temperatures below about 200 F., this curve tends to become asymptotic and the binder component itself becomes substantially solid, under atmospheric conditions. In short, it manifests the characteristics of true plasticity and plastic flow throughout the temperature range, its rate of flow being increased by heating and decreased by cooling, as is usual with all plastics. When the granular body material is added this enhances the yield value or differential pressure required (at any temperature) to initiate plastic flow of the shoe filler composition, taken and used, as a Whole.

It may be observed that ethyl cellulose, mentioned above as one of the film-forming or gel-forming constituents which may be used in the shoe filler composition of the present invention, is a commercial product which is readily obtained, In respect of its responsitivity .to heat, however, it varies somewhat, probably in terms of its specific degree of polymerization. Thus, its melting point is given as 240-255 C., whereas the manufacturers of the commercial product give its softening point as 152- 162 C., which is equivalent to 306324 F. The latter, or softening point is to be understood as the melting point as above referred to, in connection with this component of the shoe filler composition.

1 claim:

1. Method of imparting plasticity and thermoplastic flow to the binder component and to shoe filler compositions, as an entity, at a temperature of 200-300 F., which comprises the steps of dissolving a normally solid, water-resistant film-forming material of the class consisting of vinyl-chloride-vinyl acetate, ethyl cellulose and styrene polymers in the proportions of approximately 1.6% to 17% by weight, and a resin of the class consisting of common rosin, polymerized rosin, hydrogenated rosin, phenoland alkyd-resins, in a non-aqueous, nonvolatile, aromatic hydrocarbon petroleum residue solvent, having an initial boiling point above 400 F., said resinsolvent component be'mg present in the proportions of approximately 98.4 to 83% by weight, at a temperature approximating the melting point of the film-forming ma- 12. terial, thereby to form a uniform thermoplastic binder component and mixing therewith approximately 50% by volume of a granular, resilient, solid body material 2. Method of imparting plasticity and thermoplastic How to the binder component and to shoe filler compositions, as an entity, at a temperature of 200-300 F., which comprises the steps of dissolving a normally solid, water-resistant film-forming material of the class consisting of vinyl-chloride-vinyl acetate, ethyl cellulose and styrene polymers, and a resin of the class consisting of common rosin, polymerized rosin, hydrogenated rosin, phenoland alkyd-resins, in a non-aqueous, non-volatile, aromatic hydrocarbon petroleum residue solvent, having an initial boiling point above 400 F., at a temperature approximating the melting point of the film-forming material, said film-forming material being present in proportions of from 1% to 25% by weight and the solvent and resin component being present in proportions of from 99% to 75% by weight, adding a granular, resilient, body material thereto and mixing to the desired consistency.

3. Method of imparting plasticity and thermoplastic flow to the binder component and to shoe filler compositions, as an entity, at a temperature of 200-300 F., which comprises the steps of dissolving a normally solid, water-resistant film-forming material of the class consisting of vinyl-chloride-vinyl acetate, ethyl cellulose and styrene polymers in the proportions of from 1% to 25% by weight, and a resin of the class consisting of common rosin, polymerized rosin, hydrogenated rosin, phenoland alkyd-resins, in a non-aqueous, non-volatile, aromatic hydrocarbon petroleum residue solvent, having an initial boiling point above 400 F., in the proportions of from 99% to 75 by weight at a temperature approximating the melting point of the film-forming material, thereby to form a uniform, thermoplastic binder component and mixing therewith a granular, resilient, solid body material, the granular body material being of at least equal volume to the volume of the binder with which it is mixed.

4. Method of imparting plasticity and thermoplastic flow to the binder component and to shoe filler compositions, as an entity, at a temperature of 200-300 F., which comprises the steps of dissolving a resin of the class consisting of common rosin, polymerized rosin, hydrogenated rosin, phenol-and alkyd-resins, in a non-aqueous, non-volatile, aromatic hydrocarbon petroleum residue solvent, having an initial boiling point above 400 F., in the proportions of approximately 24% to 51% by weight of said resin and 49% to 76% by Weight of said solvent and a total of said resin solvent of 98.4% to 83% by weight, dissolving a normally solid, water-resistant filmforming material of the class consisting of vinyl-chloridevinyl-acetate, ethyl cellulose and styrene polymers in the proportions of approximately 1.6% to 17% by weight therein at a temperature approximating the melting point of said film-forming material, thereby to form a uniform, thermoplastic binder component and mixing therewith a granular, resilient, solid body material.

5. A shoe filler composition, characterized by consisting essentially of a uniform, thermoplastic binder component composed of a normally solid-water-resistant, filmforming material, of the class consisting of vinyl-chloridevinyl-acetate, ethyl cellulose and styrene polymers in the proportions of approximately 1.6% to 17% by Weight, and a resin of the class consisting of common rosin, polymerized rosin, hydrogenated rosin, phenoland alkydresins, and a non-aqueous, non-volatile, aromatic hydrocarbon petroleum solvent in which said film-forming material and said resin are dissolved, in the proportions of approximately 98.4% to 83% by weight of said resin solvent component, containing approximately 51% to 24% by Weight of said resin and 49% to 76% by weight of said solvent, at temperatures between 200 F. and 300 F., and a granular, resilient, solid, body material, dispersed throughout the thermoplastic binder component in the proportions of at least 50% by volume of the product.

References Cited in the file of this patent UNITED STATES PATENTS 14 Killingsworth et a1. Feb. 7, 1950 Fawcett et a1 Dec. 25, 1951 Crowell Oct. 14, 1952 Gates May 12, 1953 Hess et a1. Dec, 22, 1953 Crowell May 31, 1955 FOREIGN PATENTS Great Britain Nov. 28, 1912 

1. METHOD OF IMPARTING PLASTICITY AND THERMOPLASTIC FLOW TO THE BINDER COMPONENT AND TO SHOE FILLER COMPOSITIONS, AS AN ENTITY, AT A TEMPERATURE OF 200*-300*F., WHICH COMPRISES THE STEPS OF DISSOLVING A NORMALLY SOLID, WATER-RESISTANT FILM-FORMING MATERIAL OF THE CLASS CONSISTING OF VINYL-CHLORIDE-VINYL ACETATE, ETHYL CELLULOSE AND STYRENE POLYMERS IN THE PROPORTIONS OF APPROXIMATELY 1.6% TO 17% BY WEIGHT, AND A RESIN OF THE CLASS CONSISTING OF COMMON ROSIN, POLYMERIZED ROSIN, HYDROGENATED ROSIN, PHENOL- AND ALKYD-RESINS, IN A NON-AQUEOUS, NON- 